The present invention relates to a scroll compressor in which a plurality of compression chambers is moved with reducing volume reduced by orbital motion of a movable scroll of the compressor to draw refrigerant gas from a suction chamber to the compression chambers and then to discharge the refrigerant gas compressed in the compression chambers into a discharge chamber.
In a conventional electric scroll compressor for a vehicle air conditioning apparatus, its housing is so formed that a front housing is joined to a rear housing. A fixed scroll which is fixed to the front housing and a movable scroll which faces the fixed scroll are provided in the front housing. In addition, the front housing has a motor chamber defined therein, and in the motor chamber an electric motor is disposed. The front housing also has a suction passage formed on a lower portion thereof so as to communicate with the motor chamber.
The front housing also has a suction chamber defined therein, and the suction chamber is formed so as to communicate with the motor chamber through the suction passage. As the electric motor is operated to rotate the movable scroll around the central axis of the fixed scroll, a plurality of compression chambers formed between spiral walls of both scrolls are moved toward the center of both spiral walls with decreasing in volume thereof. During the above motion of the compression chambers, refrigerant gas is introduced into the suction chamber through the motor chamber and the suction passage and introduced from the suction chamber into the compression chambers to be compressed in the compression chambers.
The refrigerant gas compressed in the compression chambers is discharged into a discharge chamber defined by the fixed scroll and the rear housing in the housing. The refrigerant gas discharged into the discharge chamber includes lubricating oil which circulates in the housing for lubricating drive mechanism for rotating the movable scroll around the central axis of the fixed scroll. In order to avoid the lubricating oil in the refrigerant gas in the electric scroll compressor from escaping into an external refrigerant circuit of the vehicle air conditioning apparatus, an oil separator is provided in a discharge passage of the refrigerant gas. Japanese Unexamined Patent Publication No,. 2004-301090 discloses one example. If the lubricating oil is taken into the external refrigerant circuit, the lubricating oil adheres to, for example, the inner wall surface of a gas cooler or an evaporator to reduce the efficiency of heat exchange.
The above oil separator is provided with, for example, a centrifugal oil separator which separates the lubricating oil from the refrigerant gas by centrifugal separation caused by circling motion of the refrigerant gas to introduce only the refrigerant gas into the external refrigerant circuit. The lubricating oil separated from the refrigerant gas falls from the oil separator to be temporarily reserved in a lower portion of the oil separator and then returned into a back pressure chamber which is lower in pressure than the discharge chamber through a passage. The lubricating oil which has lubricated the drive mechanism in the back pressure chamber is introduced into an oil reservoir through a passage. In a region between the fixed scroll and the rear housing, the oil reservoir is defined on an outer peripheral side of the discharge chamber.
Meanwhile, in the region between the fixed scroll and the rear housing, the suction passage is formed on the lower portion of the outer peripheral side of the discharge chamber. The suction passage is surrounded by a gasket to prevent the refrigerant gas circulating in the suction passage from leaking into the oil reservoir. Therefore, the region on the outer peripheral side of the discharge chamber is partly occupied by the suction passage and is only partly occupied by the oil reservoir. Specifically, the oil reservoir can be secured only on the upside region of the gasket.